Draft device for chimney-stacks.



N0. 629,0I9. Patented luly I8, |899.

J. G. THOMAS.

DRAFT DEVICE FOR CHIMNEY STACKS.

(Application filed June 16, 189B.\ N o M u d e l rAIIIIlll/llllllllllllIl/IIIII/ llrrn OFFICE.

JOI-IN G. THOMAS, OF WASHINGTON, DISTRICT OF COLUMBIA.

DRAFT DEVICE FOR CHININEY-STACKS..

SPECIFICATION forming part of Letters Patent No.' 629,019, dated July 18,- 1899. Application iiled June 16, 1898. Serial No. 683,582. (No model.)

T0 all whom, t may concern:

Beit known that I,- JOHN G. THOMAS, a citizen of the United States of America, residing at Washington, in the District of Columbia, have invented a new and useful Draft Device for Chimney-Stacks, of which the following, taken in connection with the accompanying drawings, is a description.

The object of my invention is to provide means for increasing the draft of furnaces, especially of the locomotive type, although the device is applicable to steamboat-stacks or chimney-stacks of stationary furnaces.

A further object is to prevent what is'known as back draft of locomotives-that is,when a locomotive is running and the steam is shut off while the furnace-door is open the gas and iiame is caused by back draft to be forced in volume out of said door to thegreat discomfort of the fireman.

A still further object is to prevent the smoke from trai1ingthat is, when the locomotive or train is running and steam of the exhaust is shut off the smoke and gases from the lomotive-stack are forced by atmospheric pressure to take a downward course and not only obscure the sight of the engineer and iireman, but the same is drawn by suction caused by the momentum of the train and to pass down between the passenger-cars and in the open windows thereof to the great discomfort of the passengers.

A still further object is to provide an auxiliary draft to the exhaust-draf t of a locomotive, and thereby to a certain extent assist the said exhaust.

Another object is to partially destroy the atmospheric pressure.

I attain these objects by constructing a device that can be slipped down over the stack and secured upon the upper outer periphery thereof,or it may, if desired, be cast integral with said stacl, said device consisting of an assemblage of air-collectors formed of flaring horizontally-arranged openings at their lower ends and terminating in contracted verticallyarranged flat nozzles or slots so placed as to completely surround the upper end of the smoke-stack and constructed to extend vertically in front of said stack and inwardly at an angle of about thirty-five degrees toward the vertical center of said stack. The flaring mouths of the collectors are arranged horizontal and all open toward the front of the stack or locomotive, the result being that whgn the locomotive is running a large volume of air is collected horizontally and discharged with considerable force by reason of the contracted openings in a thin sheet over the top of the stack, in a vertical sheet at the front, and in a substantially inverted cone shape at the sides and rear thereof toward the vertical center of said stack and shooting into the ascending gases at an almost right angle thereto, thereby creating a suction that considerably assists the exhaust of the locomotive and further acts as a continuous draft when said exhaust is shut off and the locomotive is in motion.

My invention can be better understood by referring to the accompanying drawings, in

which- Figure l gives a side View of my device as applied toa locomotive-stack, showing in dotted lines the partitions therein forming airchannels. Fig. 2 is a top and plan view. Fig. 3 is a perspective view of the device applied to a stack, and Fig. 4 represents in vertical section a locomotive-stack with my device 4cast integral therewith.

This draft device consists of ahood-shaped structure entirely open at the top, either secured upon the stack B or cast integral therewith, as stated, and extending around said stack, said device being open at the front and closed in the rear. Suitably placed therein lare a number of air-collecting horizontallyarranged openings e e and e3, terminating in vertical or substantially vertical narrow elongated slots or nozzles e and e4. The flaring openings or collectors e e3 are all arranged to face in the direction of the front of the locomotive. Around the front the hood has a semicircular projection d, that extends a suitable distance above the top of front and to the rear portion of the sides of the stack, the object of this projection being to break the atmospheric pressure at the top of the stack,

y which is very strong and heavy when the locomotive is at full speed.

It will be noted, Fig. 3, that the openings or nozzles e open vertically at the top of the ridge or projection u, while those e3 at opposite sides are inclined inward about thirty- IOO iive degrees. The collectors e3 slope downward upon opposite sides of the stack and terminate in slots or nozzles e4 at the rear top of the stack. These latter nozzles, it will be seen, terminate flush with the rear top rim or edge of the stack.

When the device is cast integral with the stack,V the slots or nozzles may be arranged just beloW the upper internal edge of the stack, as shown in Fig. 4, and all open on a slight incline toward the center of said stack. It will thus be seen that according to the arrangement shown in Figs. 1 and 3 when the locomotive is in rapid motion a practically unbroken column or Wall or sheet of air, completelysurroundingthe upper end of the stack,-

and gases are not only facilitated in their ascent when the locomotive is running and they are under action of the exhaust, but after the steam is shut offA and the exhaust not Working the column of ascending air Will lift the products of combustion high above the top of the stack, thereby preventing trailing of the smoke and overcoming back draft from atmospheric pressure, thereby keeping the cab of the locomotive clear and. free from gases and ilame. It will also be readily understood by those eonversant with the steaming qualities of a locomotive that the auxiliary draft induced as described will to a very large extent relieve the exhaust, thus making it possible to enlarge the exhaust-nozzle, and thereby relieving the back pressure of steam in the cylinders.

I desire to have it understood that I do not wish to be conned to thefexact shape or configuration of the device herein shown and described. Any means may be resorted to to collect large quantities of air and force the same out in thin sheets, entirely surrounding the top of the stack, so they fall Within the scope of my invention.

Having fully described my invention,what I desire to secure and claim by Letters Patent S- I. A draft-top for locomotive-stacks, having a series of flaring, air-collecting, horizontal passages with their mouths all directed toward the frontof the stack,- such horizontal passages all communicating With and discharging through narrow vertical channels.

entirely surrounding the top of the stack, those in the f rent discharging the air straight upward While those toward and in the rear are so inclined as to discharge the air toward the center and above said stack, substantially as described.

2. A top for locomotive-stacks containing means for partially destroying atmospheric pressure, preventing the trailing of smoke and escapeinent of gas through the furnacedoor,`the same consisting of a device containing horizontal ilarin g air-collecting openings,

opening into channels tapering to small narro\v vertical nozzles encircling the entire upper end of said stack, and a semicircular ridge or projection A extending a suitable distance above the front and sides of said stack, the arrangement of said nozzles being such that a thin sheet of air is discharged straight upward over the front, and inclined toward the vertical center thereof at the sides and rear thereof, substantially as described.

` J OIIN G. THOMAS.

Vitn esses:

GEO., S. WA'rsoN, A. R. ToWNsHEND. 

